Glass processing device and bottom machine therefor for manufacturing glass containers

ABSTRACT

A bottom machine is provided for a glass processing device to manufacture glass containers from glass tubes. The bottom machine includes one or a plurality of holding units for holding the glass container or glass tube, with the holding units being mounted so as to rotate around an axis of rotation of the bottom machine in order to convey the glass container or glass tube to various processing positions, a pressure source for supplying a gas flow, a duct system communicating with the pressure source for directing the gas flow to the holding units and for feeding the gas flow into the glass tube or into the glass container, with the duct system being designed to be free of gaps.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 14/314,351filed Jun. 25, 2014, which claims benefit under 35 U.S.C. §119(a) ofGerman Patent Application No. 10 2013 212 150.4, filed Jun. 25, 2013,the entire contents of both of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a bottom machine for a glass processingdevice for manufacturing glass containers made from a glass tube,comprising one or a plurality of holding units for holding the glasstube or glass container, with the holding units being mounted so as torotate around their own axis and around an axis of rotation of thebottom machine in order to convey the glass tube to various processingpositions, a pressure source for supplying a flow of gas, and a ductsystem that communicates with the pressure source for directing the gasflow to the holding units and for feeding the gas flow into the glasstube or glass container. The invention further relates to a glassprocessing device as well as a method for manufacturing glasscontainers.

2. Description of Related Art

Glass containers that are manufactured using generic glass processingdevices have a cylindrical section or conical section. In particular,generic glass processing devices are used to manufacture glasscontainers as syringes and vials, the syringes and vials being usedprimarily for storing and administering pharmaceutical products, such asmedications.

U.S. Pat. No. 1,700,326 A, U.S. Pat. No. 2,193,376 and EP 0 293 661 A1show devices in which glass containers are obtained from a glass melt bymeans of a blowing method. In this process, a specific volume of theglass melt is placed in a mold, the glass having a very high temperature(approximately 1600° C.). A cavity is then produced by, for example,inserting a mandrel into the molten glass. Afterwards, compressed air(several bars) is blown into the cavity, so that the glass pressesagainst the walls of the mold and consequently is molded. In order toremove the resulting glass containers from the mold, it must be possibleto open the mold. Conventionally, there are two parts of the mold thatcan be opened. However, in order to prevent deformation of the glasscontainer when the mold is opened, the mold must be cooled, at least atthe contact surface between glass and mold, to a temperature thataffords the glass containers a certain degree of form stability(approximately 600° C.). Therefore, it must be possible to cool themold, which can also be conducted by way of the compressed air. Inaddition, it must be possible to remove the glass container from themold by using tongs, for example, so that there must be a certain degreeof form stability before the glass container can be removed from themold. In general, glass containers that are manufactured using theblowing method are suitable for storing pharmaceutical products.However, the glass containers resulting from the blowing method have awall thickness that varies greatly. On account of the opticaldistortions resulting from this, automated product inspection ispossible to only a very limited extent.

DE 103 41 300 B3 shows a generic glass processing device formanufacturing glass containers from a glass tube; however, in this case,no air or other gas can be fed into the glass tube.

Glass processing devices of the kind mentioned in the beginning have aparent machine and a bottom machine, both of which can rotate and have anumber of holding units, which comprise a clamp chuck, for example.Usually, the bottom machine is arranged below the parent machine. Aglass tube that is approximately 1.5 m in length is clamped in the clampchuck of the parent machine, the glass tube protruding downward from theclamp chuck by a specific length. At its downward protruding open end,the glass tube undergoes certain processing operations, which areperformed at different processing positions. To this end, the parentmachine and, together with it, the clamp chuck are rotated by a certainangle from one processing position to the next. If the downwardprotruding end of the glass tube has been completely processed, so that,for example, it has a rolled edge or a thread, then a part of the glasstube has to be severed. The corresponding clamp chuck of the parentmachine is aligned with a clamp chuck of a holding unit of the bottommachine at the processing position at which the severing step isperformed. The holding unit of the bottom machine can move axially andgrasps the glass tube somewhat above the downward protruding end of theglass tube. In the region between the clamp chuck of the parent machineand the clamp chuck of the bottom machine, a gas burner is usuallydirected at the glass tube in order to heat it, with it being possibleto heat the glass tube in other ways as well. In this case, the gasburner is placed in a fixed position. In order to heat the glass tube ina manner that is as rotationally symmetric as possible, the holdingunits can rotate around their own axis. As a result of rotating theglass tube, it is heated not only at one site by the gas burner, but theheating is distributed uniformly over the circumference. The glass tubeis heated until it is sufficiently viscous that the part that is clampedin the clamp chuck of the bottom machine can be severed from theremaining part of the glass tube by lowering the clamp chuck of thebottom machine. In the process, the heated part of the glass tube tapersand constricts to such an extent that a closed bottom forms at thesevering site, one at the drawn-off part situated in the clamp chuck ofthe bottom machine and one at the part of the glass tube remaining inthe clamp chuck of the parent machine.

In the following, the part that is situated in the clamp chuck of thebottom machine will be considered. As already discussed, the free openend is already completely processed, but the bottom of the now resultingglass container is not yet in its desired form. In this stage ofprocessing, the bottom of the glass container is situated above the openend in relation to the direction of action of gravity, this entailingthe following: As described above, the bottom is produced by a thermalsevering step, so that the viscosity of the glass in the bottom regionis still so high that the bottom sags more or less strongly downwarddepending on the diameter of the glass tube used. In addition, thebottom exhibits a radially changing wall thickness. In order to be ableto furnish the bottom of the glass container with the desiredcharacteristics, it needs to undergo yet further, primarily thermalprocessing steps. In order to counteract the sagging of the bottom, agas, usually air, is blown into the glass container through the open endof the glass container, as a result of which a back pressure thatsupports the bottom is created. Depending on which processing stepsremain to be performed, a sufficient amount of gas is blown in to causethe bottom to bulge upward, as a result of which the accessibility ofthe bottom to processing tools, such as gas burners, is increased.Finally, the glass container is brought to the desired length, thisbeing accomplished by pressing the bottom against a bottom template. Tothis end, a gas flow is fed into the glass container, resulting in thecreation of back pressure when it meets the bottom and pressing thebottom against the bottom template. However, because the glass containeris open, no significant static overpressure is created in the glasscontainer. Both the static overpressure and the back pressure amount tono more than 1 mbar.

Blowing in a gas flow has yet another aspect. Borosilicate glasses arepreferably used for storing pharmaceutical products, because they offerhigh hydrolytic resistance at relatively low cost. Borosilicate glassesalso contain sodium to lower their melting point. However, Na ions arenot bound valently in the glass, but rather migrate through the glassmatrix, which is defined primarily by SiO₂. If the glass tube is heatedto sever it, temperatures of greater than 1200° C. are necessary, suchtemperatures clearly lying above the vaporization temperature of sodium.Consequently, large amounts of Na vaporize from the bottom and depositonce again at various sites in the vial. The vaporization of sodium alsohas the effect that boron is entrained in the form of borates and alsovaporizes, even though the borates, in comparison to sodium, aremarkedly more strongly bound in the glass matrix.

The glass container is thermally treated very strongly at the bottom,whereas, at the cylindrical section, no thermal treatment takes place.As a result of this, strong thermal stresses are created in the glasscontainer, leading to potential cracking of the glass container aftercooling. In order to prevent this, a further thermal treatment needs tobe performed so as to relieve the stresses. This thermal treatment takesplace at approximately 600° C., that is, clearly below the temperaturesthat are necessary for severing the glass container from the glass tube.In the process, a large part of the sodium borate vaporizes. The partthat does not vaporize bakes into the walls of the glass container. Thisposes a problem in that Na ions can migrate into the substance stored inthe glass containers. Particularly in the case of pharmaceuticalsubstances, this is undesirable. The migration tendency strongly dependson the substances being stored in the glass containers and the pH valuethereof. As a result of introducing the gas flow into the glasscontainer or into the glass tube, part of the sodium is also removedfrom the glass container during the severing process, so that lesssodium is able to bake into the walls. In this context, the tendency forsodium to be able to migrate into substances being stored in the glasscontainers is also referred to as surface alkalinity, which can also bereduced by blowing in gas in a undefined manner.

Blowing air into the glass container or into the glass tube is conductedin known glass processing devices as follows: Below the clamp chuck ofthe bottom machine, a tube runs parallel to the axis of rotation of thebottom machine, with the outlet opening of the tube being situateddirectly below the open end of the glass tube or glass container. Placedalong the circular path traveled by the clamp chuck of the bottommachine is a correspondingly curved bottom tube furnished with a slot ora number of holes, which are arranged on the top surface. The inletopening of the tube running parallel to the axis of rotation of thebottom machine is situated at a specific distance above the bottom tube.The bottom tube is charged with gas, usually air, which leaves the slotor the holes and enters the respective inlet opening. As mentioned atthe beginning, the holding units or the clamp chucks can be rotated foruniform heating of the glass tube or glass container. The tube runningparallel to the axis of rotation of the bottom machine rotates alongwith them.

The holes are unprotected toward the top, so that they can becomequickly plugged by glass splinters, oil, and other particles that arepresent in the harsh surroundings of the glass processing machine.Consequently, the flow conditions change in the region between thebottom tube and the inlet opening, so that it is nearly impossible tofeed a reproducible gas flow from the pressure source into the glasscontainer or glass tube. It can never be known what volume flow actuallyenters the glass container or glass tube. It is noted at this point thatit depends on the progress of the processing whether the gas still isbeing fed into the glass tube or else into the already existing glasscontainer with closed bottom. Blowing is performed regardless thereof.

Not only sodium borates, but alkali borates in general have yet anotherdetrimental property. The rate of vaporization of alkali boratesincreases exponentially with increasing temperature. When the bottom ofthe glass container is processed, sodium borate vaporizes out of thebottom region and deposits once again in a condensation zone on thewalls of the glass container. The glass is already relatively cold inthe condensation zone. However, an inward diffusion zone forms betweenthe bottom and the condensation zone, in which more sodium boratediffuses into the glass than vaporizes. Consequently, there results anenrichment of sodium borate in the inward diffusion zone and a depletionin the bottom, with the depletion in the bottom having no negativeconsequences. However, the enrichment of borate in the inward diffusionzone has the following consequences:

In the near-surface region of the inward diffusion zone (approximately30 to 200 μm from the inner surface of the glass container), theenrichment of boron has the effect that the borosilicate glass, composedprimarily of Si, Na, and B, is no longer miscible after cooling, becausethere is a miscibility gap in the ternary phase diagram here.Consequently, two phases of different composition are formed, whichnecessarily also have different chemical and physical properties. One ofthe two phases also exhibits a lower hydrolytic resistance, so that itis more readily attacked, resulting in stresses in the near-surfaceregion of the inward diffusion zone. As a result of this,particle-shaped glass components detach from the surface, thesecomponents having a clearly smaller dimension in one axis than in aplane perpendicular to this axis. These particles then enter thesubstance stored in the glass container, this having particularly greatconsequences when the substance is administered as a medicine. Thetendency for detachment of these flaky particles is also referred to asthe delamination tendency.

In known glass processing devices, the machine operator in chargeadjusts the magnitude of the gas flow on the basis of his experience,such that the bottom obtains the desired geometric properties and thelimit values set for surface alkalinity are not exceeded. Anothermachine operator can achieve the same geometric properties of the bottomand the desired values of surface alkalinity with an entirely differentmagnitude of the gas flow. Reproducibility is not afforded. However, thedelamination tendency cannot be reliably lowered into uncritical rangeswith known glass processing devices and, for a long time, was not thefocus of manufacturers of glass containers for the above-mentionedpurposes.

SUMMARY

An object of the present invention is therefore to further develop aglass processing device and a bottom machine for this glass processingdevice of the kind mentioned in the beginning such that the delaminationtendency of glass containers, in particular those made of borosilicateglass, can be clearly reduced. Another object of the present inventionis to specify a method for manufacturing glass containers from a glasstube, particularly a glass tube made of borosilicate glass, by means ofwhich the delamination tendency of glass containers manufactured in thisway can be markedly reduced.

The delamination tendency of glass containers that are manufactured bymeans of the bottom machines mentioned in the beginning can be reducedby designing the duct system without gaps. As mentioned above, ductsystems of conventional bottom machines have a bottom tube and a tuberunning perpendicular thereto. On account of fabrication inaccuracies, agap is necessarily created between the bottom tube and the tube directedperpendicular to it, the dimensions of which change when the bottommachine rotates. Furthermore, particles and other foreign matter canaccumulate in the gap, something that is not unlikely owing to theextreme conditions that prevail in the surroundings of the bottommachine during glass manufacture. Consequently, unpredictable vortexes,turbulence, and splitting of the gas flow arise in the gap, so that onlya portion of the gas flow is indeed fed into the tube runningperpendicular. Therefore, it is not possible to make any reproduciblestatements about the volume flow that is actually fed into the glasscontainer or into the glass tube. On account of the gap-free design ofthe duct system of the bottom machine according to the invention, thegas flow is fed, without any interference and without any interruption,from the pressure source to the holding units and into the glass tube,so that, regardless of the rotary position of the bottom machine, thesame volume flow or the same mass of gas flow is always fed into theglass tube or into the glass container. It has been found that thedelamination tendency can be reduced when the gas flow is fed into theglass tube or into the glass container with a clearly defined, laminarflow and a specific flow rate during the various processing steps andcan also leave once again in a defined manner. This is made possible bythe gap-free design of the duct system, which could not be achieved inconventional duct systems. In accordance with the invention, thedelamination tendency can be clearly reduced without the other functionsof the gas flow, namely, the raising of the viscous bottom and thelowering of the surface alkalinity below a specific limit value, beinglost or becoming less pronounced.

In a preferred embodiment, the bottom machine according to the inventionhas a rotor and a stator, with the holding units being arranged on therotor and the duct system having a first number of subducts arranged ona rotor section and a second number of subducts arranged on a statorsection as well as a feedthrough section for gap-free conveyance of thegas flow from the stator section to the rotor section. The feedthroughsection is understood to mean the section in which the duct systemtransitions from the stator into the rotor. The stator section isunderstood to mean the section of the duct system that, when the bottommachine is in operation, is fixed in position. In accordance therewith,the rotor section is understood to mean the section of the duct systemthat rotates during operation. Consequently, the stator and rotorsections also comprise regions of the duct system going beyond thestator and rotor as such. The number of subducts arranged on the rotorsection and the number of subducts arranged on the stator section neednot be the same. In this embodiment, the gas flow can reach the holdingunit only when a subduct arranged on the rotor section overlaps or isaligned with a subduct arranged on the stator section in the feedthroughsection. As mentioned in the beginning, the glass tube or glasscontainer is transported from one processing position to the next byrotation of the rotor. The time that is required for transport from oneprocessing position to the next is usually markedly shorter than thetime during which the glass tube or glass container resides in aprocessing position. Therefore, it is sufficient when the gas can flowto the holding device only in the respective processing position.Therefore, the subducts arranged on the rotor and stator sections runsuch that they overlap only when the respective holding units and theglass tubes or glass containers clamped in them are situated in therespective processing positions or in the immediate vicinity thereof.Depending on which processing step is being carried out, a gas flow willno longer be needed, particularly when the bottom has already beencompletely processed and its temperature has cooled sufficiently so thatit has adequately solidified and no longer requires any support.Consequently, it is not necessary for a subduct on the stator section tobe assigned also to a subduct of the rotor section in each processingposition.

The combination of a rotor and a stator has a number of advantages. Inparticular, it is possible to arrange the pressure source and parts ofthe duct system, such as distributors, valves, etc., at fixed positions,which thereby become part of the stator section of the duct system. As aresult, it is possible to reduce the design expense. The holding unitsare arranged on the rotor so as to ensure that the glass tube or glasscontainer can be transported from one processing station to the next.Accordingly, it is overall possible to provide a compact bottom machinein a structurally simple manner. In particular, no rotary feedthroughsfor electrical cables are necessary. However, this embodiment entailsthe necessity of designing the feedthrough section that is arranged atthe downstream end of the stator section and at the upstream end of therotor section such that, in spite of the relative movement between therotor and the stator taking place in the feedthrough section, the ductsystem is designed so that no gap is created, which can have a negativeeffect on the gas flow and hence impede the correctly targeted feed ofthe gas flow into the glass tube or glass container. Here, however,there exist known possibilities for transferring gasses from restinginto rotating parts. Mechanical seals or piston rings can be employed inthis case in order to seal the rotor with respect to the stator and thusto ensure the flow of gas from the pressure source to the holding unitswithout any interruption. Consequently, in this embodiment, theadvantages of a rotor-stator arrangement can be combined with the idea,according to the invention, of feeding a defined gas flow into the glasstube, so that a compact bottom machine is created, by means of which thedelamination tendency of glass containers made from the glass tube canbe markedly reduced.

In an advantageous embodiment, the stator and the rotor are designedsuch that a gap seal is created in the feedthrough section to seal theduct system. It should be noted in this context that the provision of agap seal is not in contradiction with the object according to theinvention of designing the duct system to be gap-free. In contrast tothe above-described gaps of known bottom machines, the gap seal—as itsname already states—has a sealing effect, because the rotor and thestator do not exceed a specific maximum distance of separation, whichtakes into consideration the gas used, among other things, and also doesnot change substantially during operation. In addition, the rotor and/orthe stator can be provided with a specific surface design in order toenhance the sealing effect. Furthermore, the gap seal is protected, sothat no particles can penetrate into it from the outside. Gap seals havethe advantage that no sealing elements need to be used, which, onaccount of the relative movement between rotor and stator, would besubject to wear. Consequently, the reliability and the lifetime of thebottom machine according to this embodiment are increased, without anynotable disruption in the gas flow during its transition from the statorinto rotor, so that the delamination tendency of the glass containerscan be markedly reduced.

Preferably, the rotor is arranged radially outside of the stator. Thestator is thus axially accessible, so that connections, electricalcables, and other components of the stator section of the duct systemcan be arranged in a space-saving manner, yet nonetheless be readilyaccessible.

In an advantageous embodiment, one or a plurality of the subducts in thefeedthrough section have an extension running in a plane perpendicularto the axis of rotation. As already discussed above, the gas can onlyflow from the stator section into the rotor section and further on tothe respective holding unit when one of the subducts arranged on thestator section overlaps with one of the subducts arranged on the rotorsection, this typically being the case when the holding unit and theglass tube or glass container is situated in one of the processingpositions or in the vicinity thereof. The extension of the duct systemin the feedthrough section results in an enlargement of the overlapregion between the respective subduct of the rotor section and therespective subduct of the stator section, so that the time during whichthe gas flow is interrupted is reduced. As mentioned in the beginning,the gas flow serves, among other things, also to support the bottom ofthe glass container, which, on account of the thermal treatment, hassuch a low viscosity that it sags in the effective direction of theforce of gravity. If the time during which the gas flow is interruptedis reduced, the bottom is supported for a longer period of time, thishaving a positive effect on the quality of the bottom being formed.Furthermore, the shortening of the time during which the gas flow isinterrupted also reduces the delamination tendency, because, during aninterruption of gas supply into the glass container, the inwarddiffusion processes described above can once again take place. Theshorter the interruption, the shorter are also the inward diffusionprocesses, which leads to a reduced delamination tendency.

This extension in a plane perpendicular to the axis of rotation confinesa first angle, which is of a size such that the sealing effect of thegap seal is not lost. The gap seal is able to seal the gas flow in thefeedthrough section effectively only when not only does the gap size notexceed a maximum value, but also the gap stretches over a minimum area.If the first angle of the extension of a rotor or stator section ischosen to be too large, the region toward the neighboring subduct inwhich the gap seal can produce its effect is too small, so that thesealing effect of the gap seal could be lost.

Preferably, the duct system has a control or regulating device forcontrolling or regulating the flow of gas through the duct system. Inthis way, the magnitude of the gas flow can be adjusted such that thedesired effect on the glass container can be achieved in a reproduciblemanner. For example, mass flow controllers (MFC) can be utilized forthis purpose; such mass flow controllers themselves have a measurementsection and an actuator and regulate the volume flow into the glasscontainer. The mass flow controllers are usually combined with themachine control that specifies to the mass flow controllers when a givenvolume flow is to be supplied. There exists the further possibility ofsetting not only a specific volume flow, but also of traversing aprofile once the gas flow has been released. For example, it may beadvantageous to increase the volume flow of the gas flow slowly. Thecontrol or regulating device may be arranged on either the rotor orstator.

In an especially preferred embodiment, the duct system has six subductsarranged on the stator section as well as eight subducts arranged on therotor section and eight holding units, it being conventional to providemaximally the same number of processing positions and holding units, sothat the bottom machine is rotated in each case by 45°, in order totransport the glass tube or glass container from one processing positionto the next. The choice of six subducts in the stator section depends onthe fact that it is usually appropriate to feed a gas flow into theglass tube or glass container only at six processing positions. In theother two processing positions, for example, the glass container iscooled from the outside or removed from the holding unit, for whichpurpose no gas flow is required. In this embodiment, the bottom machineaccording to the invention can be integrated into existing processes inan especially easy manner.

In a preferred variant, five of the six subducts arranged on the statorsection each have an extension. As mentioned in the beginning, the glasscontainer is thereby brought to the desired length such that the bottomis pressed against a bottom template. To this end, an especially stronggas flow is required to furnish the requisite counterforce. The statorsection that is assigned to this processing position does not have anyextension and, as a result, the area of the gap seal is maximized, sothat it can also securely seal gas flows with high volume flow and highpressure.

The subduct of the stator section that has no extension does have, inthis case, a switching valve equipped with a pressure measurement andadjustment device. In this way, it is easier for the machine operator,as needed, to change quickly the pressure and the volume flow when theglass container is pressed against the bottom machine, which ultimatelyleads to a better quality of the glass container and to less reject.

In another embodiment, the rotor is arranged along the axis of rotationso as to overlap the stator. As a result of the fact that the rotoroverlaps the stator at least in part along the axis of rotation, thebottom machine can be designed with a smaller radial extension.

It is further advantageous when the rotor section and/or the statorsection has (have) a number of ring-shaped duct segments. Depending onwhere the ring-shaped duct segments are arranged, a subduct arranged onthe rotor section or on the stator section opens into the ring-shapedduct segment. As a result, a subduct is not assigned to a processingposition in which, as in the case of the embodiment, the rotor isarranged radially outside of the stator, but rather each subduct isassigned to a holding unit. It is possible by means of the ring-shapedduct segments for the gas flow to be fed to the holding unit without anyinterruption regardless of the rotary position of the rotor, that is,even when the holding unit is situated between two processing positions,thereby further improving the quality of the resulting glass container.In particular, it is possible to set the volume flow of the gas flowover all of the processing positions in an optimal manner and traversecomplex profiles.

Preferably, the ring-shaped duct segments in the feedthrough section areopen in the direction of the axis of rotation, with projections forcreation of the gap seal protruding into the ring-shaped duct segments.In this embodiment, rotors and stators arranged to overlap along theaxis of rotation can be provided with gap seals, so that the advantagesof the gap seals can also be utilized in this rotor-stator arrangement.

Preferably, the duct system has a control or regulating device forcontrolling or regulating the flow of gas through the duct system. Inthis way, the magnitude of the gas flow can be adjusted such that thedesired effect on the glass container can be achieved in a reproduciblemanner. For example, mass flow controllers (MFC), which can be part ofcontrol circuit, can be utilized to this end. There exists thepossibility of setting not only a specific volume flow, but also oftraversing a profile, which is particularly advantageous in the case ofrotors and stators arranged so as to overlap, because, in this case, thegas flow can be varied using a control or regulating device, without anyinterruption, during the entire processing operation carried out withthe bottom machine. The optimal volume flow can be set at any time,which leads to qualitatively especially high-grade glass containers withvery small delamination tendency.

In another embodiment, the duct system has another pressure source forsupplying a further gas flow, which can be engaged to join the first gasflow by means of a pressure measurement and adjustment device. Asalready mentioned in the beginning, the length of the glass container isadjusted by pressing the glass container against a bottom template.Required for this purpose is a stronger gas flow than for the otherprocessing steps, this stronger gas flow being supplied by engaging theother gas flow to join it. The pressure measurement and adjustmentdevice makes it easier for the machine operator to engage the other gasflow, as needed, and to adjust its strength.

Preferably, the bottom machine has eight subducts arranged on the statorsection, eight ring-shaped duct segments, eight subducts arranged on therotor section, and eight holding units. Because conventional bottommachines also have eight holding units, the bottom machine according tothe invention, which likewise has eight holding units, can be especiallywell integrated into existing processes.

In this case, it is especially advantageous when the duct system haseight control or regulating devices and eight pressure measurement andadjustment devices. As already described above, another pressure sourcecan be engaged in order to increase the volume flow. In this embodiment,all eight holding units can be charged with an increased volume flow.

In another embodiment, the duct system has exactly one subduct arrangedon the stator and a control or regulating device on the rotor forcontrolling or regulating the flow of gas through the duct system. Inthis embodiment, the distribution of the gas flow from one subduct to aplurality of subducts is conducted first on the rotor. This affords theadvantage that only one subduct needs to be transferred in thefeedthrough section from the stator section into the rotor section,thereby simplifying the sealing. In this case, a slip-ring seal can beutilized. It is further possible to operate at higher pressures, so thata higher volume flow can be directed from the stator to the rotor.Furthermore, there is less pressure loss. This affords the advantagethat the subducts can have a smaller diameter in comparison to the otherembodiments, thereby making possible a more compact structural design ofthe device according to the invention in this embodiment. Anotheradvantage that ensues from the arrangement of the regulating device onthe rotor is that the control or regulation of the gas flow is carriedout closer to the site at which the gas flow leaves the duct system andis fed into the glass container or glass tube. Pressure losses, whichcan occur on the pathway from the pressure source through thefeedthrough section into the rotor, can be corrected by the regulatingdevice. Consequently, the desired volume flow can be adjusted moreprecisely in this embodiment, which, in turn, leads to a reduction inthe delamination tendency. Obviously, it is also possible to provide aplurality of subducts on the stator or the stator section and to arrangethe regulating device on the rotor. Furthermore, exactly one regulatingdevice can be provided on the rotor or the rotor section and thedistribution of the gas flow can be arranged downstream of theregulating device. Alternatively, the distribution of the gas flow canbe carried out on the rotor and a regulating device can be provided foreach holding unit.

In another embodiment of the bottom machine according to the invention,the duct system has a free end, it being possible for the holding unitto rotate relative to the free end. As mentioned in the beginning, thetube running parallel to the axis of rotation of known bottom machinescan rotate together with the holding unit. Hence, no relative rotationof the glass tube or glass container takes place around the tube. If thetube is not aligned with the axis of rotation of the glass tube or glasscontainer or if the tube confines an angle with the axis of rotation,the gas flow will not be fed ideally into the glass tube or into theglass container and a non-rotationally symmetric flow is created withinthe glass tube or glass container, which, in an unfavorable case, canlead to dead spaces or turbulence.

If, in the case of the bottom machine according to the invention, theglass tube or glass container is rotated around the free end of the ductsystem when the gas flow is fed in, the effect of not having the gasflow ideally fed in is uniformly distributed, so that, in turn, arotationally symmetric flow is created in the glass tube or glasscontainer. In this way, the delamination tendency is noticeably reducedeven when the gas flow is not fed in ideally.

Another aspect of the invention relates to a glass processing device formanufacturing glass containers from a glass tube, comprising a parentmachine and a bottom machine according to one of the preceding exemplaryembodiments. The advantages and technical effects that can be achievedusing the glass processing device according to the invention correspondto those that have been described for the bottom machine according tothe invention. In particular, it is possible to adjust a defined gasflow during the processing of the glass tube and especially of thebottom of the glass container, so that the delamination tendency of theglass container can be markedly reduced.

The object is further achieved by a method for manufacturing glasscontainers from a glass tube by using a glass processing machine,comprising the following steps:

holding the glass tube or glass container with a holding unit andconveying the glass tube or glass container to various processingpositions by use of a transport system, and processing the glass tube orglass container at the respective processing positions, supplying a gasflow by means of a pressure source, directing the gas flow to theholding unit and feeding the gas flow into the glass tube or glasscontainer by way of a duct system that communicates with the pressuresource, the duct system being designed such that the gas flow isdirected without any gaps to the holding units.

The advantages and technical effects that can be achieved using themethod according to the invention correspond to those that have beendescribed for the bottom machine according to the invention. Inparticular, it is possible to adjust a defined gas flow during theprocessing of the bottom of the glass container, so that thedelamination tendency of the glass container can be markedly reduced. Atthe same time, it is possible to use the gas flow to support the stillhot and thus soft bottom for the further processing, so that it does notsag. Furthermore, it is possible to keep surface alkalinity of the glasscontainer below specific threshold values. It should be noted at thispoint that the gap-free directing of the gas flow reduces thedelamination tendency regardless of the transport system used, withwhich the glass tube or glass container is conveyed from one processingstation to the next. Any transport system that is suitable for conveyingthe glass tube or glass container to the processing positions can beutilized as the transport system. For example, a linear transport systemcan be utilized in this case.

Preferably, the method is carried out using a glass processing device,which has a parent machine and a bottom machine according to one of thepreviously described exemplary embodiments, with the glass tube or glasscontainer being conveyed to various processing positions by rotating thebottom machine. This embodiment of the method according to the inventionmay be implemented, in the case of the glass processing devices usuallyemployed, by using a parent machine and a bottom machine, without theneed to substantially alter the fundamental manufacturing processes. Inaddition, known parent machines can be used, so that the addedstructural expense is limited to the bottom machine.

The method according to the invention is further developed by feedingthe gas flow into the glass container such that the gas undergoeslaminar flow in the glass container and again exits the glass container.As a result of this, the glass container is continuously flushed, sothat gaseous substances, in particular alkali borates, which vaporizeowing to heating of the bottom region, when the glass container issevered from the remaining glass tube, and can diffuse in thedelamination zone into the glass of the glass container, are entrainedby the gas flow immediately after the vaporization process andtransported out of the glass container. As a result of this, thevaporized substances are prevented from diffusing back into the glassand thereby bringing about a delamination of the glass. The gas flowcoats the delamination zone with a certain protective or boundary layer.

The method according to the invention is further developed by rotationof the glass tube or glass container by the holding unit relative to afree end of the duct system when a flow of gas is fed into the glasstube or glass container. Owing to fabrication inaccuracies or dirt orowing to wear when the device according to the invention is operated, itcan happen that the lengthwise axis of the last section is not in idealalignment with the axis of rotation of the glass tube or glass containerat the free end of the duct system or a valve positioned there, and/orconfines an angle with the axis of rotation. Consequently, the gas flowwill not be fed ideally into the glass tube, resulting in the creationof a non-rotationally symmetric flow within the glass tube or glasscontainer, which can lead, in an unfavorable case, to dead spaces orturbulence, so that the delamination tendency in some regions is notreduced or is reduced only to an inadequate extent. When the glass tubeor glass container is rotated as the gas flow is fed in, the effect ofnot having the gas flow ideally fed in is uniformly distributed, sothat, in turn, a rotationally symmetric flow is created in the glasstube or glass container. In this way, the delamination tendency isnoticeably reduced even for a gas flow that is not fed in ideally.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below in detail on the basis ofpreferred exemplary embodiments with reference to the appended drawings.Shown are:

FIG. 1a a first exemplary embodiment of a bottom machine according tothe invention on the basis of a plan view, in which the middle part isshown by way of a sectional illustration,

FIG. 1b a sectional illustration along the sectional plane defined inFIG. 1 a,

FIG. 1c an illustration of the basic principle of a duct system of thebottom machine according to the invention in accordance with the firstexemplary embodiment,

FIG. 2 a schematic diagram of a glass processing device having thebottom machine according to the invention in accordance with the firstexemplary embodiment,

FIG. 3a a second exemplary embodiment of a bottom machine according tothe invention on the basis of a plan view, in which the middle part isshown with a sectional illustration,

FIG. 3b a sectional illustration along the sectional plane defined inFIG. 3a , and

FIG. 3c an illustration of the basic principle of a duct system of thebottom machine in accordance with the second exemplary embodiment,

FIG. 4a a glass container for which the vaporization, inward diffusion,and severing operations during processing are illustrated in asimplified manner, and

FIG. 4b a glass container that is processed using a bottom machineaccording to the invention.

DETAILED DESCRIPTION

Illustrated in FIG. 1a is a bottom machine according to the invention,10 ₁, in accordance with a first exemplary embodiment. The bottommachine 10 ₁ has a stator 12 and a rotor 14, which is arranged radiallyoutside of the stator 12. The rotor 14 is arranged concentrically to thestator 12 and can rotate by means of a drive unit, which is notillustrated, around an axis of rotation R, which, during operation ofthe bottom machine 10 ₁, coincides essentially with the effectivedirection of the force of gravity. The rotor 14 comprises a number ofholding units 16, each of which has a clamp chuck, which is notillustrated in greater detail, in which a glass tube, which is likewisenot illustrated in greater detail, can be clamped. The holding unit orthe clamp chuck can rotate around its own axis H. In the exampleillustrated, the rotor 14 has eight holding units 16 ₁ to 16 ₈.Furthermore, the bottom machine 10 ₁ has a duct system 18, with which agas, such as, for example, air, can be directed from a pressure source20 to the holding units 16 (see FIG. 1c ). Fundamentally suitable areall gases with which it is possible to transport substances escapingfrom the bottom out of the glass container. In the following, referencewill be made to the flow direction resulting from this. The duct system18 comprises a stator section 19, which shall comprise all ducts,distributors, subducts, etc., that pass through the stator or arearranged in a stationary manner on the stator 12, and a rotor section23, which comprises all parts of the duct system 18 that pass throughthe rotor or are arranged on the rotor 14 or are arranged so as torotate, such as, for example, a valve 56 (see FIG. 4). Shown in FIG. 1cas an illustration of the basic principle is a part of the statorsection 19, which, starting from the pressure source 20, has a duct 21,which branches into a total of six subducts 22 ₁ to 22 ₆. Arranged ineach of five of the six subducts 22 is a control or regulating device24, by means of which the volume flow of the gas that flows from thepressure source 20 to the respective holding units 16 can be controlledor regulated. The subduct 22 ₅ does not have any control or regulatingdevice 24, but rather a switching valve 26 with a pressure measurementand adjustment device 28, which is not illustrated in greater detail.The subducts 22 lead to the stator 12, in which, as can be seen fromFIG. 1b , they continue on in the perpendicular direction and bendradially outward at a certain depth.

As defined, a feedthrough section 30 is to be situated between the rotor14 and the stator 12, that is, at the point where, in the direction offlow of the gas, the stator section 19 of the duct system 18 ends andthe rotor section 23 of the duct system 18 begins. It is particularlyevident from FIG. 1a that some of the subducts 22 of the stator section19 have extensions 32 in the feedthrough section 30, which extend over afirst angle α in a plane perpendicular to the axis of rotation R, theaxis of rotation R constituting the origin of the leg of the first angleα. It can be seen that the subduct 22 ₅ does not have any extension.This very subduct 22 ₅ also has no control or regulating device 24, butinstead the switching valve 26 with the pressure measurement andadjustment device 28.

The stator 12 and the rotor 14 are constructed such that they form a gapseal 34 in order to seal the respective subducts 22 of the duct system18 in the feedthrough section 30. Alternatively, a sealing element canbe arranged between the rotor 14 and the stator 12. Downstream of thefeedthrough region 30, the corresponding subduct 22 continues in therotor section 23 of the duct system 18 and then opens to the outsidewith formation of an outlet opening 36, where tubes or hoses can beconnected via a means of connection not illustrated in greater detail.As mentioned in the beginning, the holding units 16 of the rotor 14 canalso move axially along the axis of rotation R of the bottom machine 10₁, so that, on account of their flexibility, hoses lend themselves tofeed the gas flow to the respective holding units 16.

Illustrated in FIG. 2 is a plan view of the principle of operation of aglass processing device 38 with the bottom machine according to theinvention 10 ₁ in accordance with the first exemplary embodiment.Besides the bottom machine 10 ₁, the glass processing device 38 also hasa parent machine 40. For manufacture of a glass container 42, which isnot illustrated here, a glass tube, which is not illustrated, isinitially clamped in a clamp chuck of the parent machine 40. An open endof the glass tube protrudes downward, with respect to the effectivedirection of the force of gravity, beyond the clamp chuck by a certainamount and undergoes various processing steps in order to form, forexample, a rolled edge 44 (see FIG. 4) or a thread. Once the open end iscompletely formed, the glass tube travels to a processing position A₁,in which the clamp chuck of the parent machine 40 is axially alignedwith the clamp chuck of the bottom machine 10 ₁. The clamp chucks of theparent machine 40 are usually arranged above the clamp chucks of thebottom machine 10 ₁, whence the bottom machine 10 ₁ has also been givenits name. In the original state, the glass tube has a length ofapproximately 1.5 m, so that the downward protruding part of the glasstube needs to be severed from the remaining part in order to form theglass container 42. To this end, the glass tube is heated at theappropriate site by using a gas burner, which is not illustrated. Oncethe requisite temperature has been attained, the holding unit 16 travelswith the clamp chuck of the bottom machine 10 ₁ axially upward in thedirection of the clamp chuck of the parent machine 40, so that thelatter can grasp the glass tube. Afterwards, the clamp chuck travelsonce again axially downward, with the glass tube being severed at thesite at which it has been heated, thereby forming two closed bottoms.Already in this processing position, a gas flow is fed into the glasstube via the duct system 18. The volume flow of the gas being fed invaries with the volume of the glass container. Typical volumes for glasscontainers lie between 2 mL and 100 mL. The required volume flow of thegas being fed in for this purpose lies, in this case, between 1 and 20sL/min (standard liters per minute). The pressures are adjustedcorrespondingly at the pressure source 20.

Now situated in the clamp chuck of the bottom machine 10 ₁ is the glasscontainer 42, which has the already completely formed open end 50 aswell as a closed bottom 46, which, however, does not yet have thedesired form. In order to form the bottom 46 as desired, it is treatedwith further gas burners in a targeted manner, for which purpose thebottom machine 10 ₁ travels to the processing positions A₂, A₃, and A₄.During the processing by the gas burners, a gas flow is likewise fedinto the now closed glass container 42. The gas flow can have adifferent volume flow for each processing position A₁₋₅, which can bealtered also during the time in which the glass container 42 is situatedin one of the processing positions A₁₋₄. In this process, the volumeflow can be kept constant. Once the glass container 42 has passedthrough the processing position A₄, the bottom 46 has been completelyprocessed to such an extent that the glass container 42 now can bebrought to the desired length. To this end, the glass container 42 ispressed in the processing position A₅ against a bottom template, whichis not illustrated. In order to be able to supply the requisitecounterforce, a stronger gas flow with a higher volume flow isnecessary, which, roughly, can amount to between 100 and 200 sL/min.Correspondingly arranged at the processing position A₅ is the switchingvalve 26, so that the machine operator can quickly adjust the gas flowas needed. Because a higher gas flow is present, the subduct 22 ₅ doesnot have an extension 32, so that the gap seal 34 can extend over alarger region and hence also securely seal the gas flow with the highervolume flow and higher pressure. Consequently, the second angle β, whichis confined by two adjacent extensions 32, is smaller than the thirdangle γ, which is confined by the subduct 22 ₅ and the extension 32adjacent to it (see FIG. 1a ). In the processing position A₆, the glasscontainer 42 is cooled, although this is not absolutely essential,depending on the properties of the glass container 42. The now completedfinished and largely cooled glass container 42 is removed from the clampchuck in the processing position A₇. In the processing position A₇, itis not necessary to feed a gas flow into the glass container 42, so thatno subduct 22 is assigned to the processing position. In the processingposition A₈, generally no processing is conducted, so that, here, too,no subduct 22 is necessary.

Illustrated in FIG. 3 is a second exemplary embodiment of the bottommachine according to the invention, 10 ₂, in which the kind ofillustration corresponds to that chosen for the first exemplaryembodiment illustrated in FIG. 1. The bottom machine 10 ₂ in accordancewith the second exemplary embodiment can be integrated into the glassprocessing device 38, just like the bottom machine 10 ₁ in accordancewith the first exemplary embodiment. The processing of the glasscontainer 42 proceeds in an essentially identical manner. A keydifference is the arrangement of the rotor 14 and the stator 12. Incontrast to the first exemplary embodiment, the rotor 14 is not arrangedradially outside of the stator 12, but instead below the stator 12 inrelation to the axis of rotation R during operation, so that the rotor14 overlaps the stator 12 in the direction of the axis of rotation R ofthe bottom machine 10 ₂. In the illustrated exemplary embodiment, thestator 12 and the rotor 14 have, at least in sections, the same radialextension, as can readily be seen from FIG. 3 b.

The subduct 22 ₃, which is clearly seen in FIG. 3b and is arranged inthe stator section 19 of the duct system 18, does not bend radiallyoutward in this exemplary embodiment of the bottom machine 10 ₂, butrather traverses the stator 12, without any change in direction,parallel to the axis of rotation R and then opens into a ring-shapedduct segment 48, which is open at one end and into which a projection 52of the rotor 14 protrudes in the mounted state. The subduct 22 on therotor section 23 of the duct system 18 traverses the projection 52. Inthis case, the feedthrough section 30 comprises the ring-shaped ductsegment 48 and the projection 52, with the projection 52 protruding intothe ring-shaped duct segment 48 such that the gap seal 34 is formed. Thesubduct 22 ₃ continues on in the rotor section 23 initially axially inthe direction of flow of the gas flow and then bends radially outwardwhere it leaves the rotor 14 radially with formation of the outletopening 36. Once again, a hose can be connected at the outlet opening 36by a means of connection, which is not illustrated, in order to directthe gas flow to the holding unit 16 ₃.

In the illustrated exemplary embodiment 10 ₂, there are a total of threering-shaped duct segments 48 ₁ to 48 ₃, from which run a varying numberof subducts, arranged on the rotor section 23. Consequently, threesubducts 22, which impose a specific gas flow on the respectivering-shaped duct segment 48, are also necessary on the stator section19, it being possible to vary the gas flow by means of the control orregulating device 24. In those subducts 22 on the rotor section 23 thatrun from the same ring-shaped duct segment 48, therefore, the same gasflow is fed in, regardless of the rotary position of the rotor 14. Inthis embodiment, the ring-shaped duct segment 48 also has a distributorfunction.

The embodiment shown in FIG. 3a , however, has been chosen primarily forreasons of illustration. For example, the holding units 16 ₁ and 16 ₃hang at the same ring-shaped duct segment 48 ₃. Consequently, the feedof the gas flow into the glass tube or glass container at the processingposition A₁ cannot be varied independently of the feed at the processingposition A₃. It is preferable, therefore, to provide eight ring-shapedduct segments 48, into each of which a subduct 22 on the rotor section23 protrudes. Consequently, in this case, there are also eight subducts22 on the stator section 19, as illustrated in FIG. 3c . Thus, the gasflows can be adjusted optimally and independently of one another,regardless of the processing position A₁ to A₈ in which the glass tubeor glass container 42 is situated, the volume flows varying here, too,in the aforementioned ranges. As already mentioned above, the glasscontainer 42 is brought to the desired length in the processing positionA₅, for which purpose a stronger gas flow is necessary. In thisexemplary embodiment of the bottom machine 10 ₂, another pressure source54 is engaged by means of a respective pressure measurement andadjustment device 28 for each of the eight subducts 22 ₁ to 22 ₈ on thestator section 19, as long the glass container 42 is situated in theprocessing position.

In both embodiments of the bottom machine according to the invention, 10₁, 10 ₂, the control or regulating device 24 is arranged in the statorsection 19. However, it is also possible to arrange the control orregulating device 24, which may be designed as a mass flow controller,for example, on the rotor section 23. An actuation of the mass flowcontroller can occur via a wireless link, for example, so that no rotaryfeedthroughs for cables are necessary.

Illustrated in FIG. 4a is a glass container 42, by means of which theoperations according to the invention during the manufacturing processare to be described in greater detail. The glass container 42 isillustrated in such a manner as it is oriented in the clamp chuck of thebottom machine 10. Evident is the downward directed open end 50 of theglass container 42, which has the rolled edge 44, on which, for example,a closure can be placed. As mentioned repeatedly, the glass container 42is separated from the remaining glass tube by a thermal severingprocess, for which reason the glass container 42 has its highesttemperature on the bottom 46. The temperature T decreases toward theopen end 50, as indicated by the arrow. As likewise mentioned, thebottom 46 has to undergo further thermal processing operations after thesevering process in order to bring it into the desired form.Consequently, the bottom 46 is repeatedly heated, so that, throughout aplurality of processing steps, it has the highest temperature inside theglass container 42. The temperatures lie above the vaporizationtemperatures of several constituents of the glass used, so that sodium,in particular, vaporizes out of the bottom region, with sodiumentraining boron as well in the form of borates, so that boron alsovaporizes out of the glass. At the same time, a certain amount of sodiumand boron also diffuses back into the bottom region, the degree ofinward diffusion exhibiting a different temperature dependence than thedegree of vaporization. The arrows in FIG. 4a indicate which of the twoprocesses predominates. In the vicinity of the bottom, the vaporizationpredominates, whereas, with dropping temperature, the inward diffusionbecomes increasingly stronger and attains a maximum in a delaminationzone 58. If the temperature of the glass container 42 drops further,however, the inward diffusion also becomes increasingly weaker, becauseit becomes increasingly difficult for sodium and boron to penetrate intothe glass matrix. Below a certain temperature, neither sodium nor boroncan penetrate into the glass matrix and a deposit 60 forms on the glasssurface.

For the delamination tendency, however, the inward diffusion is thecrucial process, reaching a maximum in the delamination zone 58 at aspecific distance below the bottom region.

Illustrated in FIG. 4b is how, according to the invention, the gas flowsthrough the glass container 42. From a free end 56 of the duct system18, which may be designed as a valve 56, and represents the downstreamend of the duct system 18, the gas passes concentrically to the axis ofrotation of the glass container 42 through the open end 50 into theglass container 42 and flows in the direction of the bottom 46. In theprocess, the gas flow opens up in the radial direction somewhat anddistributes itself in the bottom region, so that it flows parallel tothe bottom 46 radially outward until it reaches the region of the sidewall. Afterwards, the direction of flow changes such that the gas flowsparallel to the side wall and back to the open end 50 and leaves theglass container 42. This flow may also be referred as a coaxial flow.The flow of gas adjusted in this way ensures that the substances thatvaporize out of the bottom region, particularly sodium and boron, aredischarged from the glass container 42 and cannot diffuse back into theglass or can do so only to a very small extent. The delamination zone 58is coated with a boundary layer of the gas flow and the concentration ofsodium and boron in the glass container 42 is reduced to such an extentthat the inward diffusion still taking place does not lead to anoticeable delamination tendency. The depletion of the bottom 46 withrespect to sodium and boron has a negative effect. The creation of theflow described here in the glass container 42 presupposes the presenceof the bottom 42. However, it may nonetheless be advantageous, alreadyprior to the formation of the bottom, to feed the gas flow into thestill open glass tube in order to remove any alkali borates that may bepresent in the glass tube. Nor need the bottom 42 necessarily becompletely closed. Small openings, such as those present in the case ofsyringes, do not interfere with the creation of the flow described hereor do so only to a negligible extent when the opening does not exceed acertain size. The relationships illustrated in FIG. 4b represent theideal case. However, because the valve 56, in practice, can never feedin the gas flow in a manner that is precisely concentric with the axisof rotation of the glass container 42, a non-rotationally symmetric andnon-coaxial flow is established, as a result of which, in the mostunfavorable case, there is no protective flow over the delamination zone58. This negative effect can be markedly minimized by rotation of theglass container 42 around its axis of rotation, with the free end or thevalve 56 of the duct system 18 remaining fixed in position.

The outer diameter of the valve 56 has to be sufficiently small incomparison to the inner diameter of the open end 50 such that the airthat is blown in can readily flow out once again in a coaxial flow,without creating a backup. Because the gas that is fed in must skirt thecylindrical section of the glass container at a certain flow rate, thevolume flow is proportional to the diameter of the glass container.When, in order to adjust the length, the bottom is pressed against thetemplate, the process responsible for the delamination is alreadycompleted, so that a coaxial flow is no longer needed.

As mentioned in the beginning, it is known how to feed gas flows intothe glass container 42 during the manufacturing process. On account ofthe gaps that the known bottom machines have within the duct system,however, it is not possible to feed a flow like that illustrated in FIG.4b into the glass container 42. In particular, it is not possible toestablish a flow that remains continuously constant. Instead, aturbulent flow is produced, which leads to back pressures, turbulence,and dead spaces, as a result of which vaporized sodium and boron cannotbe removed from the glass container 42.

LIST OF REFERENCE SYMBOLS

-   10, 10 ₁, 10 ₂ bottom machine-   12 stator-   14 rotor-   16, 16 ₁-16 ₈ holding unit-   18 duct system-   19 stator section-   20 pressure source-   21 duct-   22, 22 ₁-22 ₈ subduct-   23 rotor section-   24 control or regulating device-   26 switching valve-   28 pressure measurement and adjustment device-   30 feedthrough section-   32 extension-   34 gap seal-   36 outlet opening-   38 glass processing device-   40 parent machine-   42 glass container-   44 rolled edge-   46 bottom-   48 ring-shaped duct segment-   50 open end-   52 projection-   54 further pressure source-   56 free end, valve-   58 delamination zone-   60 deposit-   A, A₁-A₈ processing position-   H axis of rotation of holding unit-   R axis of rotation of rotor-   T temperature-   α first angle-   β second angle-   γ third angle

What is claimed is:
 1. A bottom machine for a glass processing devicefor manufacturing glass containers from a glass tube, comprising: one ora plurality of holding units for holding the glass container or theglass tube, with the holding units being mounted so as to rotate aroundtheir own axis and around an axis of rotation of the bottom machine inorder to convey the glass container or the glass tube to variousprocessing positions, a pressure source for supply of a gas flow, a ductsystem communicating with the pressure source for directing the gas flowto the holding units and for feeding the gas flow into the glass tube orinto the glass container, wherein the duct system is free of gaps. 2.The bottom machine according to claim 1, further comprising a rotor anda stator, with the holding units being arranged on the rotor and theduct system having a first number of subducts arranged on a rotorsection and a second number of subducts arranged on a stator section,and a feedthrough section for the gap-free directing of the gas flowfrom the stator section to the rotor section.
 3. The bottom machineaccording to claim 2, wherein the stator and the rotor are designed suchthat they form a gap seal in the feedthrough section for sealing theduct system.
 4. The bottom machine according to claim 3, wherein therotor is arranged radially outside of the stator.
 5. The bottom machineaccording to claim 2, wherein the first or second subducts have anextension running in a plane perpendicular to the axis of rotation ofthe bottom machine in the feedthrough section.
 6. The bottom machineaccording to claim 5, wherein the extension confines a first angle in aplane perpendicular to the axis of rotation of the bottom machine. 7.The bottom machine according to claim 1, wherein the duct system has acontrol or regulating device for controlling or regulating the flow ofgas through the duct system.
 8. The bottom machine according to claim 2,wherein the duct system has six subducts arranged on the stator section,eight subducts arranged on the rotor section, and eight holding units.9. The bottom machine according to claim 8, wherein five of the sixsubducts arranged on the stator section each have an extension.
 10. Thebottom machine according to claim 9, wherein the subduct of the statorsection that has no extension has a switching valve with a pressuremeasurement and adjustment device.
 11. The bottom machine according toclaim 3, wherein the rotor is arranged along the axis of rotation of thebottom machine so as to overlap the stator.
 12. The bottom machineaccording to claim 11, wherein the rotor section and/or the statorsection have a number of ring-shaped duct segments.
 13. The bottommachine according to claim 12, wherein the ring-shaped duct segments inthe feedthrough section are open in the direction of the axis ofrotation of the bottom machine and projections protrude into thering-shaped duct segments to create the gap seal.
 14. The bottom machineaccording to claim 11, wherein the duct system has a control orregulating device for controlling or regulating the flow of gas throughthe duct system.
 15. The bottom machine according to claim 11, whereinthe duct system has another pressure source for supplying a further gasflow, which can be engaged to join the gas flow by a pressuremeasurement and adjustment device.
 16. The bottom machine according toclaim 11, wherein the bottom machine has eight subducts arranged on thestator section, eight ring-shaped duct segments, eight subducts arrangedon the rotor section, and eight holding units.
 17. The bottom machineaccording to claim 16, wherein the duct system has eight control orregulating devices and eight pressure measurement and adjustmentdevices.
 18. The bottom machine according to claim 1, wherein the ductsystem has exactly one subduct arranged on the stator and a control orregulating device on the rotor for controlling or regulating the flow ofgas through the duct system.
 19. The bottom machine according to claim1, wherein the duct system has a free end and the holding unit canrotate relative to the free end.
 20. A glass processing device formanufacturing glass containers from a glass tube, comprising: a parentmachine, and a bottom machine according to claim 1.